Anthocyans are among the most important polyphenolic compounds in berries. They may be present in berries in an amount of up to 5000 mg/kg fresh weight. The aglycones (anthocyanidins) most commonly occurring in nature are: pelargonidin, cyanidin, delphinidin, peonidin, petunidin, malvidin. The anthocyanidins present in plants are glycosidically bound. Berries contain approximately 15 different anthocyans.
Anthocyans are found in particularly elevated concentration in the fruits (berries) of plants of the Vaccinium genus. The fruits of the blueberry (Vaccinium myrtillus) have a particularly high anthocyan content. The other species of the Vaccinium genus also have high contents of anthocyans. These include the North American highbush blueberry or cultivated blueberry (Vaccinium corymbosum), cowberry (Vaccinium vitis-idaea), common cranberry (Vaccinium oxycoccos), large cranberry or bearberry (Vaccinium macrocarpon), small cranberry (Vaccinium microcarpum), false berry (Vaccinium gaultheroides), bog blueberry (Vaccinium uliginosum), big huckleberry (Vaccinium membranaceum), red huckleberry (Vaccinium parvifolium), sparkleberry (Vaccinium arboreum), ohelo berry (Vaccinium reticulatum), and the Canadian blueberry (Vaccinium myrtilloides).
Anthocyans a capable of scavenging free radicals and stabilizing them by the conjugated double bond system, so interrupting free radical chain reactions. A protective function relative to proteins has been postulated. Polyphenols prevent or inhibit the formation of carbonyl compounds, which are capable of reacting with free amino groups and thus irreversibly modifying proteins. Polyphenols reduce lipid peroxidation and function as free-radical scavengers (J. Agric. Food Chem., 2004, 52, 7419-7424: Inhibition of protein and lipid oxidation in liposomes by berry phenolics). This effect was confirmed unambiguously in vitro, the anthocyans of the blueberry (bilberry) proving the most effective, followed by raspberries, lingonberries and blackcurrants. Consumption of fresh strawberries (240 g), freeze-dried bilberries (100 g) and berry juices increases the antioxidative capacity of the blood plasma by up to 30% (Current Nutr. & Food Sci., 2005, 1, 71-86: Potential Health Benefits of Berries).
The blueberry is known in natural medicine for its healing action in the case of diarrhea and gastrointestinal diseases, and is used in the widest possible range of medical fields, for example atherosclerosis, cataract, diabetes mellitus, diarrhea or retinopathy.
Polyphenols or anthocyans are also described in connection with cardiac conditions (CVD) and cancer. They are said to have a positive, preventative effect on the development of these diseases (Antioxidant Activity of Plant Extracts Containing Phenolic Compounds, J. Agric. Food. Chem., 1999, 47, 3954-3962). In an in vitro study, phenolic extracts of different berries were tested for their action against the cell lines HT29 (intestinal cancer cells) and MCF7 (breast cancer cells). It has been demonstrated that all the extracts had a sequentially increasing inhibitory action on cell growth in concentrations of 0.025 to 0.5% (J. Agric. Food Chem., 2004, 52, 7264-7271: Inhibition of Cancer Cell Proliferation in Vitro by Fruit and Berry Extracts and Correlations with Antioxidant Levels). Furthermore, it was possible to demonstrate that anthocyan-rich foodstuffs have a preventative action in vivo and in vitro on various types of cancer in the digestive tract (gastrointestinal tract) (oral, esophageal, intestinal, colorectal) (summarized in J. Agric. Food Chem, 2005, 53, 2859-2866: Analysis of Anthocyanins in Rat Intestinal Contents-Impact of Anthocyanin Chemical Structure on Fecal Excretion).
It is known from folk medicine that elderberry and cranberry extracts are used to alleviate urinary tract diseases. This action is likewise attributed to anthocyans.
Bioavailability
If it is to be possible to use anthocyans for medical purposes and for preventing gastrointestinal diseases, it is necessary to ensure the bioavailability of the anthocyans. This depends above all on how and to what extent they are absorbed and metabolized. The bioavailability of anthocyans is on average 0.5% when administered orally to humans (summarized in Fleschhut, J., Untersuchungen zum Metabolismus, zur Bioverfügbarkeit und zur antioxidativen Wirkung von Anthocyanen (“Investigations into metabolism, bioavailability and antioxidative action of anthocyans”), thesis, 2004). Compared with flavonoids, anthocyans have a very low bioavailability. The β-D-glycosidic form is of vital significance in terms of the bioavailability and kinetics of anthocyans (J. Agric. Food Chem., 2006, 54, 583-589: Fate of Anthocyanins and Antioxidant Capacity in Contents of the Gastrointestinal Tract of Weanling Pigs Following Black Raspberry Consumption; J. Agric. Food Chem, 2005, 53, 2859-2866: Analysis of Anthocyanins in Rat Intestinal Contents-Impact of Anthocyanin Chemical Structure on Fecal Excretion). Beta-glucosidases, which are present in the body, cleave the glycosidic residues and form aglycones. Some studies show that, after oral administration, the glycosidic form of the anthocyans is absorbed (Am. J. Clin. Nutr., 2001, 920-926: Anthocyanins are absorbed in glycated forms in elderly women: a pharmacokinetic study), but is also recovered in intact, unmodified form in urine and blood.
Absorption of individual anthocyans is determined by the chemical properties of the aglycone and of the sugar residue. Absorption of the anthocyans proceeds both in the stomach and in the small intestine (Current Nutr. & Food Sci., 2005, 1, 71-86: Potential Health Benefits of Berries).
WO 96/36433 describes an encapsulation product with a shell, which is derived from microbial cell wall material. A substance is encapsulated which is not naturally present in the microbe. In addition, the shell is colored with a dye in such a way that the coloration is visible in the product. To produce the product, a grown, intact microbe is brought into contact with the substance to be encapsulated and a dye. The microbe is preferably alive at the beginning of the encapsulation process and their viability may be hindered for instance by irradiation. In any event, the microbe must be intact and must not be present in lysed form. The cell substance which has passed into solution during encapsulation is separated by centrifugation prior to drying.
U.S. Pat. No. 5,288,632 and EP 0 242 135 describe the production of a microbially encapsulated material in a grown, intact microbe with a lipid content of less than 40%, encapsulation proceeding in the absence of a plasmolyser or an organic lipid-extending substance. The microbe is present in grown form, i.e. it was recovered from the culture medium and is intact (not lysed). During production, the substance to be encapsulated diffuses through the cell wall and is retained passively within the microbe.
EP 0 453 316 describes a method of encapsulating lipophilic substances within yeast cells, whose intracellular components have been eluted by a heat treatment in the range of between 30 and 100° C. for at least one hour, in the presence of or in the absence of an elution promoter. The yeast extract is preferably isolated prior to contact with the lipophilic substance.
EP 1 454 534 describes microcapsules of microorganisms which have foreign substances encapsulated in the microorganisms and to whose surface saccharides, sweeteners, proteins and sugar alcohols are attached. In the method, first of all the foreign substances are incorporated into the microorganisms, and then the saccharides, sweeteners, proteins and sugar alcohols are attached. The attached substances bring about a modification of release behavior.
EP 0 566 347 describes the encapsulation of dyes in yeast ghosts. For this purpose, yeast debris is purified in a special process, so as then to encapsulate the dyes. During the process, the cell substances which escaped during autolysis are removed.
WO 2006/83666 describes encapsulation of a mixture consisting of 50 mg curcumin, 60 mg blueberry extract, 250 mg grapeseed extract, 375 mg green tea extract and 125 mg apple extract in gelatine capsules. Use thereof is described as a nutritional supplement for preventing and alleviating cardiovascular diseases and inflammatory processes.
WO 2006/43858 describes the use of mixtures of various plant extracts, containing for example cowberry (2-4%), for detoxifying cells, enhancing the antioxidative status of the body and stimulating intracellular biotransformation of xenobiotics. Use proceeds in the form of gelatine capsules.
RU 2 257 909 describes the use of blueberry extract with a flavonoid content of 5 wt. %. It is administered on a pharmaceutical carrier in the form of capsules, tablets, granules and the like. The product has a medical application.
EP 1 537 789 describes the microencapsulation of carotenes, tocopherols, extracts of Passiflora incarnata, (apigenin, luteolin, or the corresponding glycosides) and extracts of Vaccinium myrtillus (delphinidin). The shell may consist of natural, semi-synthetic or synthetic materials. Natural shell materials are for example gum arabic, agar-agar, agarose, maltodextrins, alginic acid or the salts thereof, for example sodium or calcium alginate, fats and fatty acids, cetyl alcohol, collagen, chitosan, lecithins, gelatin, albumin, shellac, polysaccharides, such as starch or dextran, polypeptides, protein hydrolysates, sucrose and waxes. Semi-synthetic shell materials are inter alia chemically modified celluloses, in particular cellulose esters and ethers, for example cellulose acetate, ethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose and carboxymethylcellulose, and starch derivatives, in particular starch ethers and esters. Synthetic shell materials are for example polymers such as polyacrylates, polyamides, polyvinyl alcohol or polyvinylpyrrolidone.